Error Code P0739: What It Means & What To Do?

<<See All OBD Codes

Low speeds, engine stalling, reduced power and harsh gear shifts are the prime indications of OBD code P0739 error getting stored in the PCM (Powertrain Control Module) due to problematic transmission control system and speed output.

OBD-II Code Transmission may not shift properly is defined as a TCM Engine Speed Output Circuit High.

The ECM activates P0739 and associated codes when it monitors one or multiple conditions outside a specific electrical range within the Engine Speed Sensor or its circuit. Given the nature of the code and the location of the sensor, I would say most times this would be an electrical issue. Specific mechanical issues may cause this code but i would say they are somewhat rare. P0739 TCM Engine Speed Output Circuit High code is set when the ECM monitors a higher than desired specific electrical value within the Engine Speed output circuit.

What causes this problem with the TCM Engine Speed Output Circuit High?

• Faulty Engine Output Speed Sensor
• Engine Output Speed Sensor harness is open or shorted
• Engine Output Speed Sensor circuit poor electrical connection
• Faulty Crankshaft Position Sensor

1. Crank Position Sensor - Faulty crankshaft sensor will cause transmission problems and thus affect the overall vehicle performance. Buy new crank position sensor now!
2. Speed Sensor - Speed sensors are important to inform the transmission system about the engine speed and gear transitions. Thus, check and replace faulty sensors now!
3. Transmission Control Module - TCM failure can lead to irregular shifts and can even cause severe damages to engine and transmission. Buy and replace new control module now!
4. Engine Wiring Connectors - Replace faulty connectors and make sure that the wiring is properly attached. Buy new connectors from us.
5. Diagnostic Tools - Use factory grade tools to diagnose OBD code P0739 error. Buy new tools form us.
6. Powertrain Control Module - P0739 error code can also flash due to rare problems with the PCM. Replace faulty PCM related components immediately.

We at Parts Avatar have listed out few common symptoms associated with TCM Engine Speed Output Circuit High.

Common Symptoms

• Low engine speed
• Engine stalling/bucking
• Wrong speedometer reading
• Affected throttle response

Have a look at some ways with which you can correct the P0739 code:

• Changing transmission fluid and filter
• Fixing transmission fluid leaks
• Replacement of engine speed output sensor
• Replacement of transmission output speed sensor
• Repair or replace damaged wiring and/or connectors
• Replacement of faulty shift solenoids
• PCM/TCM replacement

There is no need to get strained if your OBD Code is still flashing up as we are here at your service. Have a look at our superior variety of Shift Solenoid, Powertrain Control Module, Transmission Control Module, Turbo, Oil Pressure Sensor and many more. Now all your problems would vanish within no time.

Here are some steps which you should follow in order to diagnose this P0739 fault code:

• A scanner (or code reader), a digital volt/ohmmeter, and possibly an oscilloscope will be helpful in diagnosing this code. Some OBD-II equipped automobiles utilize an engine output speed sensor to provide the PCM with an engine output speed signal
• Begin your diagnosis with a visual inspection of system wiring, connectors, and components. Repair or replace any open, shorted, damaged, or corroded items as required and retest the system to make sure that repairs were successful.
• Inspect wiring and connectors that have been contaminated due to engine oil or transmission fluid leaks, burned on hot exhaust pipes, or damaged due to road debris. If the system wiring, connectors, and components appear to be in normal working order, connect the scanner to the diagnostic connector and record all stored trouble codes and freeze frame data.
• After the codes are cleared, operate the vehicle to see if the code returns. If the code fails to immediately return, you may have an intermittent condition. Intermittent conditions can prove to be quite a challenge to diagnose and in extreme cases may have to be allowed to worsen before a correct diagnosis can be made. If the code immediately returns, check for reference voltage and ground signals at the engine output speed sensor.
• If either the reference voltage or ground circuits are open, use the digital volt/ohmmeter to check for continuity (disconnect all related control modules from the circuit before checking circuit resistance or controller damage may occur) and resistance in both circuits.
• Repair or replace system circuits/connectors as required and retest the system to ensure that repairs were successful. Using the manufacturer’s wiring diagram for the engine output speed sensor, test all related circuits and the sensor itself for resistance and continuity and compare your findings with manufacturer’s specifications.
• Repair or replace system circuitry, connectors, and/or components that fail to coincide with manufacturer’s specs. Always retest the system to ensure a successful repair. If all system circuits are intact, connect the oscilloscope and observe live engine output speed sensor data.
• Watch for glitches or “soft spots” in the wave form pattern and repair or replace system circuitry, connectors, or components as required. If all circuits coincide with manufacturer’s specifications, and the waveform pattern is within acceptable limits, suspect a defective PCM.
• Remember that PCM failure is rare and replacement will require reprogramming. Also check for TCM failure and repair or replace as required.

Common Mistakes When Diagnosing the P0739 Code

• Engine Output Speed Sensor faulty
• Engine Speed Sensor harness is open or shorted
• Speed Sensor circuit poor electrical connection
• Faulty Crankshaft Position Sensor
• Faulty PCM and TCM